U.S. patent application number 10/168207 was filed with the patent office on 2003-07-10 for secure transaction systems.
Invention is credited to Hawthorne, William McMullan.
Application Number | 20030130955 10/168207 |
Document ID | / |
Family ID | 27255725 |
Filed Date | 2003-07-10 |
United States Patent
Application |
20030130955 |
Kind Code |
A1 |
Hawthorne, William
McMullan |
July 10, 2003 |
Secure transaction systems
Abstract
A bank card transaction system comprises a first apparatus (10)
for use by a card holder and a second apparatus (18) for use by the
card issuer. One of these apparatus (e.g. the card holder's
apparatus) is arranged for creating an encrypted number,
corresponding to at least part of a card number, and the other
apparatus is arranged for decrypting the encrypted number upon
receipt thereof. The encrypted number is given to the merchant by
the card holder, e.g. over the Internet, and is then passed by the
merchant to the card issuer for authorisation in the usual way:
identifying information is passed over a separate communication
link established direct from the card holder to the issuer, to
enable the card issuer to decrypt the encrypted card number upon
receipt.
Inventors: |
Hawthorne, William McMullan;
(Dartmouth, GB) |
Correspondence
Address: |
David P Gordon
65 Woods End Road
Stamford
CT
06905
US
|
Family ID: |
27255725 |
Appl. No.: |
10/168207 |
Filed: |
October 15, 2002 |
PCT Filed: |
December 18, 2000 |
PCT NO: |
PCT/GB00/04864 |
Current U.S.
Class: |
705/65 |
Current CPC
Class: |
H04L 9/3234 20130101;
G06Q 20/04 20130101; G07F 7/1016 20130101; G06Q 20/367 20130101;
H04L 9/3226 20130101; H04L 2209/56 20130101; G06Q 20/425
20130101 |
Class at
Publication: |
705/65 |
International
Class: |
G06F 017/60 |
Foreign Application Data
Date |
Code |
Application Number |
Dec 17, 1999 |
GB |
9929723.6 |
May 19, 2000 |
GB |
0012011.2 |
Oct 3, 2000 |
GB |
0024097.8 |
Claims
1. A bank card transaction system which comprises a first apparatus
for use by a card holder and a second apparatus for use by the card
issuer, one of said apparatus being arranged for creating an
encrypted number, corresponding to at least part of a card number,
and the other said apparatus being arranged for decrypting the
encrypted number upon receipt thereof.
2. A system as claimed in claim 1, arranged for providing a card
number to a merchant to effect a transaction, and also arranged to
establish separate communication with the card issuer's
apparatus.
3. A system as claimed in claim 2, further comprising apparatus for
use by the merchant and arranged for providing said card number,
received from the card holder, to the card issuer.
4. A system as claimed in claim 2 or 3, in which the card holder's
apparatus is arranged randomly to generate a transaction number to
form part of a card number for provision to the merchant, the card
holder's apparatus being further arranged to encrypt the
transaction number or card number and transmit the encrypted number
to the card issuer's apparatus.
5. A system as claimed in claim 4, in which the card holder's
apparatus is arranged to transmit one or more items of information
to the card issuer's apparatus, to enable the latter to identify
the card holder.
6. A system as claimed in claim 2 or 3, in which the card issuer's
apparatus is arranged randomly to generate a transaction number
which it then encrypts and transmits to the card holder's
apparatus, and the card holder's apparatus is arranged to decrypt
the encrypted transaction number and then include the transaction
number in a one-time card number for provision to the merchant.
7. A system as claimed in claim 2 or 3, arranged for provision of
an alternative card number to the merchant, the card holder's
apparatus being arranged to encrypt the alternative number or a
part thereof and transmit the encrypted number to the card issuer's
apparatus.
8. A system as claimed in any one of claims 2 to 7, in which the
card holder's apparatus is arranged to transmit the value of the
transaction to the card issuer's apparatus.
9. A system as claimed in claim 8, in which the card holder's
apparatus is arranged to transmit the value of the transaction in
encrypted form.
10. A system as claimed in any one of claims 2 to 9, in which the
card holder's apparatus is arranged to perform a hash function on
the order placed with the merchant, and transmit this to the card
issuer and optionally to the merchant.
11. A system as claimed in claim 1, in which the card holder's
apparatus is arranged to encrypt part of the holder's card number
and provide a reconstructed card number, which includes the
encrypted part, to the merchant, together with one or more items of
information identifying the card holder.
12. A system as claimed in claim 11, further comprising apparatus
for use by the merchant and arranged for providing said
reconstructed card number and said identifying information to the
card issuer.
13. A system as claimed in any preceding claim, arranged such that
the encryption is performed using a key which is augmented by a
salt, the salt being transmitted with the encrypted number.
14. A system as claimed in any preceding claim, in which the card
holder's apparatus holds, in encrypted form, a Unique Personal Key
for the card holder, and said card holder's apparatus is arranged
to decrypt this upon entry of a password or PIN, the decrypted
unique personal key then being used as encryption or decryption
key.
15. A system as claimed in claim 13, in which the card issuer's
apparatus is arranged to recreate the card holder's Unique Personal
Key, at each transaction, for use as decryption or encryption
key.
16. Apparatus for use by a card holder in a system as claimed in
claim 1, the apparatus being arranged for creating or decrypting an
encrypted number, corresponding to at least part of a card
number.
17. Apparatus for use by a card issuer in a system as claimed in
claim 1, the apparatus being arranged for creating or decrypting an
encrypted number, corresponding to at least part of a card
number.
18. A transaction system for performing on-line transactions,
between an organisation and a customer thereof, the system
comprising a first apparatus for use by a customer and a second
apparatus for use by the organisation, one of said apparatus being
arranged for creating an encrypted number, corresponding to at
least part of a customer number, and the other said apparatus being
arranged for decrypting the encrypted number upon receipt
thereof.
19. A transaction system as claimed in claim 18, in which said
first apparatus is arranged to generate a transaction number to
form part of a customer number for transmission to said second
apparatus, and said first apparatus is also arranged to encrypt
said transaction number or customer number and transmit said
encrypted number to said second apparatus.
20. A system as claimed in claim 18, in which said first apparatus
is arranged to transmit one or more items of information to said
second apparatus, to enable the latter to identify the
customer.
21. A system as claimed in claim 18, in which second apparatus is
arranged randomly to generate a transaction number which it then
encrypts and transmits to said first apparatus, and said first
apparatus is arranged to decrypt the encrypted transaction number
and then transmit the transaction number in plain to said second
apparatus.
22. A system as claimed in claim 18, said second apparatus is
arranged to perform the encryption using a key which is augmented
by a salt, the salt being transmitted with the encrypted
number.
23. A system as claimed in claim 18, in which said first apparatus
holds, in encrypted form, a Unique Personal Key for the customer,
and said first apparatus is arranged to decrypt this upon entry of
a password or PIN, the decrypted Unique Personal Key then being
used as encryption or decryption key.
24. Apparatus for use by a customer in a system as claimed in claim
18, the apparatus being arranged for creating or decrypting an
encrypted number, corresponding to at least part of a respective
customer number.
25. Apparatus for use by a service-providing organisation in a
system as claimed in claim 18, the apparatus being arranged for
creating or decrypting an encrypted number, corresponding to at
least part of a respective customer number.
Description
[0001] The present invention relates to systems for use to effect
transactions in a secure manner: in particular, the invention
relates to systems for use when effecting transactions, whether
on-line or off-line, using bank cards, (including credit
cards,debit cards and charge cards); further, the invention relates
to systems for use when effecting transactions, whether on-line or
off-line, using bank cards (including credit cards, debit cards and
charge cards); moreover, the invention relates to systems for use
when effecting on-line transactions with a service-providing
organisation, such as a bank, utility company etc.
[0002] Each of the above transactions currently lacks security, in
that information supplied by a customer can be re-used by anyone
who comes into possession of it.
[0003] Considering bank cards in particular, conventionally these
are used in a variety of ways, as follows:
[0004] 1) Off-line, the original method used in shops, petrol
stations and other retail outlets. The merchant produces a docket
by taking an impression of the buyer's card, and the buyer signs
this docket to provide authentication and agreement to the
transaction. The merchant may obtain authorisation for payment, by
telephone or datalink, from the card issuer;
[0005] 2) On-line, by reading the required information from the
magnetically encoded stripe of the card and communicating this
information, together with the value of the purchase, to the card
issuer to obtain authorisation for the transaction;
[0006] 3) On-line, by communicating the order and delivery
information together with card details over the Internet;
[0007] 4) By post, by filling in a coupon with the order and
delivery information together with card details; and
[0008] 5) By telephone, the order and delivery information together
with card details being given orally over the telephone.
[0009] Each of the above methods lacks security, in that the
information supplied by the buyer can be re-used by anyone who
comes into possession of it, to make fraudulent purchases against
the buyer's card.
[0010] We have now devised systems for ensuring security in respect
of purchases or transactions carried out using bank cards.
[0011] In accordance with the present invention, there is provided
a bank card transaction system which comprises a first apparatus
for use by a card holder and a second apparatus for use by the card
issuer, one of said apparatus being arranged for creating an
encrypted number, corresponding to at least part of a card number,
and the other said apparatus being arranged for decrypting the
encrypted number upon receipt thereof.
[0012] Preferably the card itself is of conventional form, enabling
it to be used in any of the conventional ways discussed above.
However, where the system in accordance with the present invention
is available to both the card holder and the card issuer, then the
card can be used for a secure transaction to be carried out, the
true card number not being divulged to the merchant or to any party
other than the card issuer.
[0013] In a preferred embodiment, for use in performing
transactions over the Internet, the card holder's apparatus is
arranged to generate a random number which forms part of the card
number passed to the merchant: we will call this random number part
a transaction number. Typically the card number which is
transmitted to the merchant consists of 16 digits, made up of an
initial e.g. 6 digits identifying the card issuer, followed by the
transaction number (e.g. 8 digits), followed by an e.g. 2- or
1-digit check sum. The card number received by the merchant is
passed on by him to the card issuer, typically via his card
acquirer and the card regulator (e.g. VISA or MASTERCARD). The card
holder's apparatus also initiates a communication direct to the
card issuer and transmits, over this link, the same "card number"
(or the transaction number) in encrypted form, together with
information to identify the card holder (e.g. a reference number
for the card holder): the card issuer's apparatus is thus able to
identify the card holder and retrieve information, from its
customer records, to decrypt the encrypted "card number".
[0014] In a modified or second embodiment, the card issuer's
apparatus may be arranged to generate a random transaction number,
encrypt this and pass the encryption to the card holder: the card
holder's system decrypts the encrypted transaction number and
includes the random transaction number, in plain, in a one-time
"card number" transmitted to the merchant and onwards to the card
issuer, for checking against the random transaction number earlier
generated.
[0015] In a third embodiment, the card holder is provided with a
supplementary card number identifying his card: we will call this
card number an alternative card number and it is used only for
transactions in accordance with the invention. Thus, the
alternative number is an identifying number provided to the card
holder in addition to the usual card number (which continues to be
used for conventional transactions). Indeed, the account may be set
up specifically for electronic transactions, without necessarily
issuing a card, in which case the alternative number identifies the
account, or a virtual card, rather than a real card. Nevertheless,
the alternative number has the same number of digits as a
conventional bank card, consisting typically 6 digits identifying
the card issuer, followed by 8 digits identifying the card holder,
and finally 2 digits serving as a check sum.
[0016] In use in effecting a transaction, the alternative number is
sent to the merchant and passed on by the merchant to the card
issuer, for authorisation in the usual way. In order to provide for
security, however, the card holder or buyer's computer is arranged
to establish communication direct with the card issuer, bypassing
the merchant and card regulator. Over this link, the card holder's
computer sends the alternative number (or the account-identifying
part thereof) in encrypted form. The apparatus or system at the
card issuer decrypts the encrypted alternative number (or part
thereof) which it receives direct from the card holder: the
issuer's system is then able to confirm that the buyer is in the
process of effecting a transaction, and accordingly processes the
request for authorisation being made by the merchant, on the basis
of the same alternative number.
[0017] The card holder or buyer's system also transmits information
in plain to the card issuer, in addition to the encrypted form of
the alternative number (or card-identifying part thereof), so that
the card issuer is able to identify the card holder and so retrieve
data from its own customer records to enable it to decrypt the
encrypted number. This information may comprise a reference number
for the card holder.
[0018] In a fourth embodiment, the card holder's apparatus encrypts
the unique part of the card number and passes the reconstructed
card number to the merchant, together with information to identify
the card holder (such as his reference number): all of these items
of data are passed on by the merchant to the card issuer. The
apparatus at the card issuer is arranged to decrypt the encrypted
part of the card number, and so recover the true card number: the
recovered card number is then authenticated against the card number
held in the card issuer's file for the card holder. The card
issuer's apparatus then checks the value of the proposed
transaction against the card holder's financial status and so
authorise the transaction, and record the transaction against the
card holder's account.
[0019] In each of the above embodiments, preferably the encryption
key is different for each transaction. Accordingly, whilst an
unauthorised person may gain possession of the information relating
to one transaction, this information cannot be used again, because
the card number encryption will be inapplicable for such further
uses. The variation of the encryption key may be derived by
augmenting it with a salt, which may be the date and time generated
from a time clock of the apparatus used for performing the card
number encryption, or a random number generated by that apparatus.
The use of the salt ensures that the encryption key is
substantially different each time it is used. The salt is
transmitted together with the encrypted number, to permit
decryption of the latter.
[0020] When issuing new cards, preferably the apparatus at the card
issuer is arranged to generate, for each new card holder, a Unique
Personal Key. Preferably this is generated from a master key and
from one or more items of open information related to the card
holder, for example selected from the card holder's reference
number, name, address, telephone number, bank account number, card
expiry date, etc. Preferably the card issuer's apparatus is
arranged to encrypt the Unique Personal Key using an access PIN or
password for the card holder. The card is sent to the card holder:
also the encrypted Unique Personal Key is sent to the card holder
and (preferably separately) the access PIN or password is sent to
the card holder.
[0021] Preferably the card holder's apparatus is arranged to allow
the card holder to change his access PIN or password as and when
desired: in particular, the card holder will normally wish to
change his initial access PIN immediately after receiving this from
the card issuer. For this purpose, preferably the apparatus is
arranged to authenticate the current PIN and only then call up the
stored encrypted Unique Personal Key, decrypt this with the
correctly-entered current access PIN or password, then re-encrypt
this with a newly-entered access PIN or password: the newly
encrypted Unique Personal Key is then stored in place of the
previous encryption.
[0022] In carrying out each transaction, the apparatus used by the
card holder is arranged to use the access PIN or password, when
entered correctly by the card holder, to decrypt the encrypted
Unique Personal Key. Preferably this apparatus is arranged to use
the Unique Personal Key and the above-mentioned salt for encryption
or decryption purposes.
[0023] The apparatus at the card issuer is arranged to recover the
card holder's Unique Personal Key, either by retrieving it from the
card holder's file using the reference number or other identifying
information, or by recreating it from the master key and the
relevant items of information used to create it initially. Then the
apparatus is able to use the recovered Unique Personal Key and the
salt in order to decrypt the encrypted number which it receives
during the course of the transaction.
[0024] We have also devised systems for ensuring security in
respect of transactions carried out on-line between customers and a
service-providing organisation (e.g. a bank for on-line
banking).
[0025] Thus also in accordance with the present invention there is
provided a transaction system for performing on-line transactions,
between an organisation and a customer thereof, the system
comprising a first apparatus for use by a customer and a second
apparatus for use by the organisation, one of said apparatus being
arranged for creating an encrypted number, corresponding to at
least part of a customer number, and the other said apparatus being
arranged for decrypting the encrypted number upon receipt
thereof.
[0026] Embodiments of the present invention will now be described
in more detail, by way of examples only, partly with reference to
the accompanying drawing, the single figure of which is a schematic
diagram to explain a secure transaction over the Internet in
accordance with one embodiment of the invention.
[0027] For a new card holder, the card issuing authority creates a
card which carries the holder's name, the card number and the card
expiry date, all this information being embossed on the card and in
human-readable form. In common with present practice, the card
number consists of 16 digits, the first 6 digits identifying the
card issuing authority, the next 8 digits being unique to the card
holder, and the final 2 digits being a check sum. The card may
include a magnetically encoded stripe and optionally a chip, and
also an area for the card holder's signature. The card is
accordingly of conventional form and may be used in all the
conventional ways: the card issuing authority also generates a
conventional PIN number to enable conventional use of the card, for
example in a cash machine.
[0028] In addition, an electronic apparatus at the card issuing
authority is arranged to create a Unique Personal Key for the card
holder. This Unique Personal Key (typically 48 to 96 digits in
length) is generated from a master key (typically 960 digits in
length) together with one or more items of information related to
the card holder, such as a reference number for the card holder,
the card holder's name, address, telephone number, card number and
expiry date.
[0029] The electronic apparatus at the card issuing authority is
also arranged to generate an initial access PIN number or password
for the card holder (in addition to the PIN required for
conventional use of the card).
[0030] The card issuing authority sends the card to the card holder
and also sends the card holder software for running the system,
together with a reference number for the card holder, the encrypted
Unique Personal Key and preferably the encrypted card number: the
software and data items may be sent on-line or on a CD, for
example. Preferably separately, the card issuing authority sends
the card holder a note of the initial access PIN or password.
[0031] In accordance with conventional practice, apparatus at the
card issuer stores a card account file for the card holder, which
includes the card holder's reference number, name and address,
telephone number, bank account number, card number, card expiry
date, credit rating etc. This apparatus may or may not store the
Unique Personal Key, according to the card issuer's policy. The
initial access PIN or password is not stored.
[0032] In order to increase the security of the master key, a
number of such keys may be in use at any one time. For example, the
Unique Personal Key for cards having a first expiry date would be
generated from master key 1, cards having the second expiry date
would be generated from master key 2, and so on. If each card has
an expiry date 2 years after its date of issue and successive
expiry dates are one month apart, for example, then there would be
24 master keys in use at any one time. The first master key would
become redundant at the end of the first expiry month, and so on.
It will be appreciated that the card holder's Unique Personal Key
and initial access PIN or password change with each re-issue of his
card.
[0033] For placing an order over the Internet, the card holder
uses, in his PC, the software and other information which was
supplied to him. The software requires the card holder to enter his
access PIN or password: if this PIN or password is accepted, the
software enables the card holder to proceed with placing the order.
It will be noted that the card holder's access PIN or password is
used by his PC to permit him to proceed and place an order over the
Internet, but also serves to decrypt the encrypted Unique Personal
Key. The card holder's security software enables the card holder to
change his access PIN or password as and when desired: in
particular, the card holder will normally wish to change his
initial access PIN or password immediately after first receiving
this from the card issuing authority.
[0034] Referring to the drawing, the card holder's computer 10 is
connected to the Internet via his Internet service provider ISP and
over the Internet to the merchant's website 12. In the usual
manner, the card holder, acting as buyer, visits the merchant's
website in order to ascertain the goods or services on offer and
the prices of these. The buyer proceeds to place an order: when he
elects to pay, he is required to enter his credit or debit card
details and the merchant obtains authorisation from the card issuer
18, typically via a card acquirer 14 and the card regulator 16.
[0035] In accordance with the present invention, the card holder's
security software is arranged to generate an 8-digit random number,
which we will call a transaction number. In the Internet
transaction under consideration, at the point in the procedure that
the card holder (as purchaser or buyer) decides to pay, he confirms
this by performing an appropriate keystroke or using the mouse to
click on an appropriate box on the screen. Then his security
software causes a reconstructed 16-digit "card number" to be sent
to the merchant, and onwards to the card issuer 18 in the
conventional manner (i.e. via his Internet service provider ISP and
the merchant's website 12 and possibly, as in the example shown,
via the acquirer 14 and card regulator 16). However, the
reconstructed "card number" which is sent from the card holder's
computer 10 consists of the usual initial 6 digits identifying the
card issuer, followed by the randomly generated 8-digit transaction
number, followed finally by a 2-digit check sum (resulting from the
check sum algorithm run on the preceding 14 digits). In the usual
manner, the card holder's software causes his computer 10 to send
his name and card expiry date.
[0036] After terminating the connection with the merchant, the card
holder's security software causes his computer to initiate a
connection D directly to the card issuer 18, bypassing the
merchant's website 12 and the traffic handling stations (acquirer
and regulator). The card holder's security software encrypts the
random transaction number, using the card holder's Unique Personal
Key and a salt, then transmits the encrypted transaction number
directly to the card issuer 18. The card holder's software may
similarly encrypt, and transmit direct to the card issuer, one or
more other items of information, e.g. selected from the card
holder's name, the true card number, the account reference number,
and a message sequence number. In addition, the card holder's
security software causes the computer 10 to transmit; in plain,
both an open identifier (e.g. the card holder's reference number)
to enable the card issuer's system to identify the card holder, and
the salt. From the reference number or other identifier, the card
issuer's system is able to retrieve or recreate the card holder's
Unique Personal Key to enable it, with the salt, to decrypt the
encrypted transaction number and any other encrypted information
transmitted to it from the card holder's PC. The card issuer's
system then adds the transaction number and other information to a
record of transactions which it is ready to process.
[0037] Upon receipt of the "card number" in the usual way from the
merchant's website 12, the card issuer's system makes a comparison
between the 8-digit transaction number in this and its record of
transaction numbers which it is ready to process. If there is a
match, then the card issuer's system proceeds to process the
proposed transaction in the conventional manner.
[0038] The card issuer's system may be required firstly to process
the encrypted transaction number received direct from the card
holder (or buyer), before receiving the usual request from the
merchant. Instead or in addition, the card issuer's system may be
arranged that, if it receives the transaction request first from
the merchant, it holds this request until it has received and
processed the communication direct from the buyer.
[0039] In the above-described arrangement, a predetermined digit of
the transaction number may be of a predetermined value, to
distinguish the reconstructed card number from a true card
number.
[0040] Preferably, as described, the transaction number encryption
is salted and the salt is transmitted in plain by the card holder's
computer 10 direct to the card issuer 18. The salt is variable and
most conveniently may comprise a date and time stamp generated by
the card holder's PC.
[0041] In a second embodiment of the system for effecting a
transaction over the Internet, again the software of the card
holder's or buyer's PC 10 initiates the second communication link D
direct to the card issuer 18, after the buyer has decided to effect
payment to the merchant: the buyer's software causes his PC to
transmit, in plain, the card or account holder's reference number
or other information to identify him. In response, the card
issuer's system 18 generates a random 8-digit transaction number to
be used as a one-time number and encrypts this using the card
holder's Unique Personal Key (retrieved from the system's file for
the card holder or recreated from his reference number, name, card
number and expiry date and other information and the master key, as
previously described): this encrypted transaction number,
preferably prefaced with the usual 6 digits identifying the card
issuer and followed by the usual 2-digit check sum, is transmitted
over the link D to the card holder's computer, together with the
salt (preferably a date and time stamp and/or a random number) used
in the encryption. The card holder's software decrypts the
encrypted transaction number, using the card holder's Unique
Personal Key and the salt, and transmits a one-time "card number"
to the merchant in plain, consisting of the 6 digits identifying
the card issuer, the 8-digit random transaction number and a final
2-digit check sum. This one-time number is handled in the same way
as an ordinary card number and is passed on by the merchant 12 to
the card issuer 18, typically via the acquirer 14 and regulator 16,
together with the card expiry date and transaction value. The card
issuer 18 checks whether the 8-digit transaction number, in the
one-time card number thus received from the merchant, matches the
random number with it generated for the transaction and, in the
event of a match, proceeds to process the proposed transaction.
[0042] In the above-described embodiments, the data communicated by
the merchant 12 to the card issuer 18 is no greater than the data
presently communicated over this route(essentially consisting of a
16-digit "card number", card expiry date and the value of the
proposed transaction).
[0043] As an additional security measure in each of the
above-described embodiments, preferably the value of the proposed
transaction is also communicated direct to the card issuer 18, for
checking with the payment value requested by the merchant 12.
Preferably the transaction value is encrypted (using the Unique
Personal Key and the salt).
[0044] As a further measure, the software in the card holder's
computer 10 is preferably arranged to perform a hash function on
the order, the resulting hash being typically of 4 or 6 digits:
this hash is then transmitted, in plain, to the merchant 12 and, in
encrypted form, direct to the card issuer 18, where it is stored.
If subsequently a dispute arises between the buyer and the merchant
in respect of any aspect of the transaction (e.g. the product type
or number of products or price), then the issuer is able to
arbitrate on the basis of the stored hash.
[0045] In a third embodiment, which also uses a direct
communication link D to the card issuer 18 in addition to the
communication link to the merchant, the card holder is issued with
a supplementary card number, which we will call an alternative card
number, in addition to the usual or true card number provided for
conventional transactions. The alternative card number may be
provided to the card holder by inclusion in the software provided
to him, or may be provided in some alternative secure manner and
then entered by the card holder into his computer 10. The
alternative card number has 16 digits, like a true card number:
also like a true card number, the first 6 digits of the alternative
card number identify the card issuer and the final two digits
represent a check sum (resulting from the predetermined checking
algorithm run on all the preceding digits). The middle 8 digits
form the transaction number.
[0046] Thus, in carrying out a transaction over the Internet, then
the alternative card number is sent by the card holder's computer
10 to the merchant and onwards to the card issuer 18. Also, the
transaction number from the alternative card number is encrypted
using the card holder's Unique Personal Key and a random salt and
transmitted, direct to the card issuer 18, together with the card
holder's reference number and the salt in plain. The card issuer's
system 18 is able to identify the card holder from the reference
number and so is able to retrieve or recreate his Unique Personal
Key. Using the recovered Unique Personal Key and the salt, the card
issuer's system 18 then decrypts the encrypted transaction number.
The card issuer's system 18 is then ready to authorise the
transaction and adds the transaction number to its record of
transactions which it is ready to process, as described
previously.
[0047] Each of the above-described embodiments may be used for
placing an order or effecting a transaction with the merchant
off-line. Thus, the card holder will communicate direct with the
card issuer on-line in the manner described above, for each
embodiment, but the information which the merchant requires from
the card holder is given to the merchant off-line (e.g. over the
telephone or through the post or at a point-of-sale) rather than
on-line.
[0048] A fourth embodiment of the invention, for placing an order
over the Internet, will now be described. In this embodiment, the
software in the card holder's PC initiates the transmission, to the
merchant, of the first 6 digits of the true card number (to
identify the card issuing authority) followed by an 8-digit
encryption of the next 8 digits of the card number, followed by a
2-digit check sum. The intermediate 8-digits of the card number are
encrypted using the Unique Personal Key and a salt. The software
also causes the card holder's reference number and the salt to be
transmitted in plain to the merchant, together with the card expiry
date.
[0049] The electronic processing apparatus at the merchant is
arranged to pass on, to the card issuer, information consisting of
the card holder's reference number, the salt, the card expiry date,
and the 16 digit "card number" which now includes the encryption of
the intermediate 8-digits of the true card number.
[0050] Upon reception of the above information, the apparatus at
the card issuer uses the card holder's reference number, from the
received information, to retrieve or recreate the card holder's
Unique Personal Key. The apparatus now uses the recovered Unique
Personal Key and the received salt in order to decrypt the 8-digit
encrypted part of the card number. The apparatus is arranged, in
accordance with conventional practice, to provide authentication by
checking the decrypted card number against the true card number
held in the card holder's file. Then the proposed purchase or
transaction is checked against the card holder's current credit
status in order to authorise the transaction, and the transaction
is recorded in the card holder's account. The card issuer's
apparatus furthermore stores, in its file for the card holder,
either the salt used for the transaction, or the 8-digit encrypted
part of the card number, or both the salt and the 8-digit encrypted
part of the card number.
[0051] In addition to use for placing an order over the Internet or
by other electronic communication, the above-described fourth
embodiment may be used for placing an order or effecting a
transaction with the merchant off-line, particularly ordering over
the telephone or through the postal services or at a point-of-sale.
In such cases, the card holder uses his PC to run the security
software, firstly to log on using his access PIN or password in the
manner described above. Then the security software causes the PC to
recover the Unique Personal Key, using the holder's access PIN or
password: then the security software causes the PC to encrypt the
8-digit unique part of the holder's card number, using the
recovered Unique Personal Key and a salt, as described above; the
PC then displays and/or prints out the encrypted card number and
the salt. The card holder is now able to place an order orally over
the telephone, preferably quoting his reference number, name, card
expiry date, the salt and the encrypted card number. Alternatively,
the card holder may write this information on an order form, for
posting, faxing or otherwise communicating to the merchant. The
merchant enters the received information into his system, which
then passes on, to the card issuer, the card holder's reference
number, the salt, card expiry date and "card number", for
processing in the manner described above.
[0052] The card holder may, if he wishes, generate a number of card
number encryptions and corresponding salts, all in one session, for
the purpose of placing a succession of orders as and when
required.
[0053] Instead of requiring the use of a PC, the card holder may be
supplied with a portable device, preferably a hand-held device,
programmed to perform the security calculations for the card
holder. Thus, the device includes a memory for storing the
encrypted Unique Personal Key and the card number. The device
requires the card holder to enter his access PIN or password to
enable the device: then the card holder uses the device to generate
a card number encryption and output this together with the salt
which is used. The device may have a time clock or random number
generator, which is used for deriving the salt. The device is also
arranged to enable the card holder to change his access PIN or
password in the manner described above.
[0054] The bank card may be in the form of a smart card which
includes a chip which stores the card holder's reference number,
encrypted Unique Personal Key and other relevant information. The
card may then be used with a host machine, for example a cash
machine or a point-of-sale register, which requires the card holder
to insert his card and enter his access PIN or password, following
which the machine firstly verifies the access PIN, decrypts the
Unique Personal Key and then generates the encrypted card number
and corresponding salt. The cash machine then communicates the card
holder's reference number and the salt to the card issuer, together
with the encrypted card number and any other relevant information.
The card issuer uses the reference number to identify the card
holder and so retrieve or recreate this Unique Personal Key, then
uses this and the salt to decrypt the encrypted card number, for
checking against the true card number held in its file for the card
holder. If this matches, then the transaction is allowed to
proceed.
[0055] Each of the four embodiments described above may be used for
on-line transactions over the Internet, for example between a card
or account holder and a bank. Thus, the card or account holder's
computer would in such cases communicate directly with the bank or
other financial institution issuing the card or holding the account
(this institution corresponding to, or in some cases being the same
party as, the card issuer shown in the drawing). In each of the
four embodiments, all communication is with the financial
institution, rather than with any merchant. The card holder's
software is arranged, on establishing communication with the
financial institution, to transmit the card holder's reference
number so that the financial institution can identify the card
holder. The four embodiments would be arranged to operate as
follows.
[0056] In the first embodiment, the random transaction number (or
"card number" including the random transaction number) is
transmitted, together with the salt, and also the encrypted
transaction number (or "card number"): the system at the financial
institution recovers the Unique Personal Key and uses this, with
the salt, to decrypt the encrypted transaction number, for
comparison with the transaction number received in plain; if there
is a match, the transaction is allowed to proceed.
[0057] In the second embodiment, the system at the financial
institution uses the card holder's reference number to recover his
Unique Personal Key, and uses this and a salt to encrypt a random
transaction number, which is sent (with the salt) to the card
holder: the card holder's computer uses his Unique Personal Key and
the salt to decrypt the transaction number, which is then sent back
in plain to the financial institution for comparison with the
transaction number originally generated there.
[0058] In the third embodiment, the card holder's computer sends
the encrypted alternative card number and a salt to the financial
institution: using the card holder's reference number, the system
at the financial institution recovers the Unique Personal Key and
uses this, with the salt, to decrypt the alternative number and
compare this with the alternative number held in its file for the
card holder.
[0059] In the fourth embodiment, the card holder's computer sends
the encrypted true card number and a salt: the system at the
financial institution uses the card holder's reference number to
recover his Unique Personal Key then uses this, with the salt, to
decrypt the encrypted true card number, for checking against that
held in its file for the card holder.
[0060] Whilst the above description relates to on-line bank
transactions, the respective embodiments may be used, in
corresponding manner, for on-line transactions between a customer
and any service-providing organisation (e.g. a utility company, the
tax office, etc) in which he has an account or customer number. In
such cases, the customer number replaces the "card number" referred
to in the above description.
* * * * *